1. Field of the Invention
The present invention relates to semiconductor wafer processing equipment and, more particularly, to a conductive feedthrough extending from volume containing atmospheric pressure through a ceramic body into a vacuum chamber.
2. Description of the Background Art
A semiconductor wafer processing system generally contains a vacuum chamber within which is mounted a wafer support pedestal or susceptor. The pedestal is used to support the wafer within the chamber during processing. The pedestal contains various components which provide heating and/or cooling of the wafer as well as clamping (chucking) of the wafer to retain the wafer in a stationary position upon the pedestal surface. Such clamping is provided by either a mechanical clamp or an electrostatic chuck. Within the vacuum chamber, the space above the pedestal where the wafer is processed is generally maintained at a high vacuum. However, the space below or inside the pedestal is maintained at atmospheric pressure.
For high-temperature reactions, such as high temperature physical vapor deposition, the pedestal is fabricated of ceramic. Heretofore, there has not been a convenient nor practical solution for providing an electrically conductive, yet vacuum sealed, connection through a ceramic pedestal such that electrical current can be passed from the atmosphere side of the pedestal to the vacuum side of the pedestal without violating the integrity of the vacuum.
Therefore, there is a need in the art for apparatus that provides a conductive feedthrough connection through a ceramic body , such as a ceramic pedestal, and a method of fabricating the feedthrough.